The proposed research concerns interactions between DNA and the proteins involved in the replication and morphogenesis of filamentous bacteriophages, and the proteins regulating structure and function in eukaryotic chromosomes. To be sought is knowledge of the structures of multisubunit-protein-DNA complexes, with emphasis on the chemical groups critically involved in binding and knowledge of the kinetics and thermodynamics of the formation of such complexes. The methods will be analytical centrifugation, ultraviolet absorption and circular dichroism, light scattering, chemical modification, and electron microscopy.